High‐Loading Cu Single‐Atom Engineering on g‐C₃N₄ for Visible‐Light CO₂ Photoreduction

COOH formation, thereby optimizing reaction thermodynamics. As a result, under visible-light irradiation, Cu-modified CN achieves a CO production rate of 14.65 µmol g⁻¹ h⁻¹, representing an 11.3-fold enhancement over pristine CN. This work not only establishes an efficient approach for synthesizing high-loading single-atom catalysts but also provides fundamental insights into the mechanistic role of single-atom sites in photocatalytic CO₂ reduction.